Hypothermia and rhabdomyolysis following olanzapine injection in an adolescent with schizophreniform disorder

Hypothermia and rhabdomyolysis are infrequent adverse effects of antipsychotic drugs. Here we report a case of an adolescent with schizophreniform disorder who developed both of them simultaneously after intramuscular injection of olanzapine. A 17-year-old male patient was hospitalized for treatment of psychotic symptoms, which persisted on risperidone 3 mg/day for 3 weeks. Then his antipsychotic drug was shifted to oral olanzapine 10 mg/day. The next day, he received intramuscular injection of olanzapine 5 mg and soon developed hypothermia, rhabdomyolysis, hypotension and bradycardia. These symptoms subsided gradually in the next 2 weeks after supportive treatment was given. Such adverse effects were not observed in the following 7 months. Possible pharmacological mechanisms were discussed. Physicians should be cautious about patients' clinical symptoms after giving olanzapine injection or rapid titration in dosage.